The present invention is directed to electromagnetic apparatuses, and especially to electromagnetic apparatuses employing a plurality of windings for handling multiple phases. Electromagnetic apparatuses that handle a plurality of winding currents are useful in many products, such as by way of example and not by way of limitation, multi-phase DC-DC converter products and AC-DC converter products.
In products employing electromagnetic apparatuses, as with many products in today's market, size of products is ever smaller. Responding to pressure to reduce product size is manifested in reduction in the sizes of components in products. Electromagnetic apparatuses using cores and windings to establish electromagnetic fields are among the bulkiest of components and are difficult to reduce in size because of the physics involved in their design. That is,
                              B          ~          L                ⁢                  I          NA                                    [        1        ]                            Where, L=inductance                    B=magnetic flux;            I=inductor current;            N=number of turns; and            A=cross-section area of core.                        
The physical size of a core-and-windings construction, affected by such factors as cross-section area and number of turns, in an electromagnetic apparatus or component directly bears upon the parameters that contribute to the proper operation of a product. Size may also be reduced by providing alternate core paths for AC (Alternating Current) and DC (Direct Current) currents within a compounded core structure. Multi-phase electromagnetic products further resist size reduction because they require a plurality of core-and-windings constructed devices.
There is a need for a reduced-size compact structure for an electromagnetic apparatus.
There is a need for a reduced-size compact structure for an electromagnetic apparatus that can support multi-phase operations.